Mission impossible: modding a Unimog

[bandit86]

Well if not impossible, really really hard

info: 1970 Unimog 406. 110 hp 5.6L diesel inline 6 witha 6 speed transmission. 6.5:1 gears. Originally engine governed to 2500rpm, current engine to 2800 rpm. Has 40 inch tires and a top speed of 85 kms per hour. I can play with the governor to top it out at 3100 rpm max. Fuel economy? Hahahah.

So, the mission is to make it highway friendly. 8000 pounds of truck. The tires are weather cracked so I need new tires. I'm looking at 395/85r20 tires. Either Goodyear mvt ot Michelin XML. They are 46 inch diameter the Goodyear looking like more street friendly and the Michelin more offroad inspired. I like both. Not sure which to get.
The air filter is oil bath, that has to go
it would need a 4 foot airdam to get close to th ground so that is out.

Suggestions and ideas? This is so underpowered I slow down to 25mpg on hills that my passable doesn't even notice

[UFO]

Oil bath air filters are very effective. I've yet to see data that shows filter restriction affects fuel mileage on a diesel.

Perhaps you can decrease your rolling resistance by making sure your wheelbearings are well lubricated, and gets some good slippery synthetic lube in your transmission and differentials. Make sure your brakes aren't dragging. Get your operating temperature up to 190F, turn your fuel down if the engine smokes, get some biodiesel in the fuel tank for lubricity and improved cetane.

Those are the only suggestions I've got.

[Gasoline Fumes]

I love Unimogs! Pics?

I think the best "mod" for a Unimog is to only drive it when you really need to.

A Cummins 3.9L 4BT would give it a little more power and probably be more efficient as well. But I'd want to keep it all original if it was in good shape.

[DonR]

You're my hero.


Unimog 406 416 info

[BamZipPow]

Put an aero package on it...

[Ryland]

From what I've read, the oil bath air cleaners only have one draw back and that is that people don't understand them or take the time to clean them, but as far as cleaning the air of dust and dirt they tend to be the best air filter you can get.

Are there heavy truck tires that would fit? they would tend to give you better gas mileage then off road tires, but a vehicle like that is made to be driven off road so it would be kind of like putting road slicks on a tractor and that is pretty much what you have, a tractor with a cab and a truck bed, complete with PTO and hydraulics so you can power your backhoe and front end loader.

[JasonG]

If you can turn the fuel pressure up or swap bigger injectors, then reduce the mg/stroke of the pump it will help. If the pump isnt that adjustable, a bit more boost will help.

A full underbelly pan and axle wing/deflector should work.
Under belly pan... - Page 7 - Toyota Forums :: Toyota Nation

I never knew thew were underpowered, guess I assumed they had big Diesels.

[akwroclaw]

in the subject of tyres - the more "slick" they are, the better:

so-so ones


Michelin XTE2 365/80/R20 160 K


- thread uneven, cut partially

----
best:
Uniroyal R300 365/80/R20 160 K

Matador TH1 385/65/R22,5 160 K


thread even, not cut, roll superbly.

Of course cut and uneven grip better, but the EF is an aim.


If the UNI is underpowered, go down with the tyre profile - that means better torque on tyres and faster gear change [EF up and lighter tyres]

you can also consider skinner tyres for smaller drag.

[bandit86]

They are big diesels but not powerful ones. Even at 110 hp he egt temps get hot. 110 hp is not a lot with 8000 pounds, when the tires weigh 200 pounds each. As far as tires go I need something decent for offroad as well so I'll probably go with the Goodyear mvt. Looks like ordinary mud tire compare to the Michelin XML which looks like a tractor tire almost

[Piwoslaw]

Originally Posted by bandit86

Well if not impossible, really really hard

You're right: impossible.
Case closed.
Next, please.


Good luck!